The present invention relates to a processor system, an engine control system and a control method, and in particular to a processor system, an engine control system and a control method in which a lock-step operation or the like is performed.
In recent years, ISO26262 of the International Standards Organization has been receiving attention as functional safety standards for vehicle-mounted electronic devices and the like. The functional safety means to secure at least acceptable minimum safety even when a fault (or a failure, hereinafter called “fault”) occurs in a component of a vehicle-mounted electronic device such as a microcomputer (e.g., a MCU: Micro Control Unit) by making functional contrivance. For example, when a fault occurs, it is necessary to detect that fault within a predetermined period after the occurrence of that fault.
As an example of the functional contrivance, there is a lock-step method using a plurality of processor cores. As a related technique, Japanese Unexamined Patent Application Publication No. 2010-198131 (hereinafter referred to as “Patent Literature 1”) discloses a technique related to a processor system using a lock-step method. In the lock-step method, the same process (task) is performed in a plurality of processor cores and a fault (an error) is detected by comparing execution results of these processor cores with each other.
In the lock-step method, in general, since a plurality of processor cores operate simultaneously, the current consumption in the microcomputer increases. Therefore, there is a problem that the amount of generated heat (hereinafter called “heat generation amount”) increases in a microcomputer using a lock-step method. It should be noted that Japanese Unexamined Patent Application Publication No. 2008-217051 (hereinafter referred to as “Patent Literature 2”) discloses a technique related to a lock-step method in which the heat generation amount is reduced.